JoAnn, a 67 year old retired secretary, experienced abdominal pain that at times radiated to the back which she dismissed as indigestion. Usually energetic, she uncharacteristically complained of fatigue and, from time to time, itchiness “all over my body.”
On several occasions JoAnn’s daughter, Ashley, urged her mother to see a specialist. Mom finally agreed to make an appointment to see the doctor when the whites of the eyes turned slightly yellow.
Her mother was diagnosed with pancreatic cancer. After one and a half years of treatment for this tumor and seeing what her mother had to endure, Ashley asked the doctor, “Am I going to get cancer? Does this type of cancer run in families?
Since we all have cancers in our bodies, each of us is at risk to develop many types of tumors. Our immune system is constantly fighting cancer to prevent it from growing out of control. All too often, cancer overwhelms the immune system and grows wildly and widely. For instance, pancreatic cancer spreads most often within the abdomen, to the liver, lungs and beyond.
Most cancers develop by chance and after the age of 65. Yet, in some families cancer develops at an earlier age. In other families, certain types of cancer occur more frequently compare to the general public (for instance — breast, ovarian and colorectal cancers). Members of these families have a genetic predisposition to cancer and are at a higher risk to grow cancer.
Normal cells are assigned certain jobs to perform in our body; such as the heart muscle’s job is to pump blood. They divide in a regular fashion and if they are damaged or get old are replaced with new, healthy cells. Cancer pays no attention to the normal functions of cells; they grow unchecked, out of control and crowd out other cells.
Snapshots of Genetic Material
DNA is the indispensable hereditary material in humans found mainly in the nucleus of cells. It is present in almost every cell of the body and contains instructions on how to build and keep our bodies functioning well. When humans reproduce, their DNA in some form is passed on to their offspring.
Chromosomes are found within the cell nucleus and contain the genes you inherit from your parents. Hereditary information determines a person’s traits, such as brown hair or blue eyes. Every normal human cell contains 23 pairs of chromosomes for a total of 46 chromosomes — one set from the mother ad one set from the father.
The sex of a person is determined by two of these 46 chromosomes. A girl inherits two X-chromosomes; one from her father and one from her mother. A boy inherits one Y-chromosome from his father and one X chromosome from his mother.
Genes, segments of DNA, are located across our chromosomes. An important job of genes (approximately 25,000 of them) is to provide instructions for the manufacturing of proteins, enzymes and other substances which determine the structure and function of cells.
In some families genetic defects, called mutations, have been linked to cancer and passed on to their offspring. What’s passed on is the abnormal gene which puts the person at a higher risk to develop cancer, not the cancer itself. About 5 to 10 % of cancers are inherited because of cancerous mutations.
Genetic Testing — Who Needs to Get It?
People at risk for an inherited cancer gene should consider genetic testing for this disease, Below are risk factors if one or more first or second degree family members were diagnosed with:
- Cancer before age 50
- A BRCA1 or BRCA2 mutation
- Ethnicity — For instance, Ashkenazi Jewish ancestry is associated with breast and ovarian cancers.
- A rare cancer, such as breast cancer in a man, sarcoma or retinoblastoma (eye cancer in children)
- Family members diagnosed with the same type of cancer
- A family member with two or more different cancers
Ashley sought genetic counseling because of her mother’s diagnosis of pancreatic cancer and a family history or cancer. She told the counselors that her grandfather had colon cancer that spread to the liver and pancreas and her great-grandfather had lung cancer.
She was relieved that genetic testing did not show any evidence of gene mutation in her cells. However, because of the cancer history in her family, she remained at an increased risk to develop cancer.
To lower the chances of developing cancer, Ashley was encouraged not to smoke, maintain a normal body weight, remain physically active, reduce stress and eat nutritiously.
In the end, she was satisfied with the testing experience and the roadmap outlined by her doctors to minimize the prospect of getting cancer. The upside, Ashley has become a spokesperson for the prevention of cancer.
References
- American Cancer Society; Understanding Genetic Testing for Cancer; May 23, 2018
- American Cancer Society; Family Cancer Syndromes; 2018
Glossary
DNA, deoxyribonucleic acid,
An inherited gene mutation means that the genetic defect is present in the fertilized egg that formed the child and can be passed on to the next generation.
An acquired mutation does not come from a parent and is not passed on to the next generation. For instance, smoking causes mutations of DNA leading to an increased risk of developing lung cancer.
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.